The present invention relates to a picture-processing apparatus, a picture-processing method adopted in the apparatus and a recording medium for storing a computer program prescribing the method. More particularly, the present invention relates to a picture-processing apparatus as well as a picture-processing method adopted in the apparatus that can be used for easily carrying out processing such as 3-dimensional editing on a 3-dimensional object shown as a 2-dimensional picture, and relates to a recording medium for storing a computer program prescribing the method.
As a conventional technology, there is known a picture-processing technology called 2D (2-dimensional) painting whereby a designer and/or the like uses a computer for carrying out work similar to drawing a picture on a piece of paper by using a drawing pen or an air brush. The work to draw a picture on a piece of paper using an air brush is referred to as a picture-drawing technique by splashing a powdered coloring material.
With the conventional 2D painting, however, a picture representing a displayed 3-dimensional object is treated as a picture on a 2-dimensional plane. Thus, when a character is drawn over the picture or a drawing is added to the 2-dimensional picture without considering orientations and other attributes in the 3-dimensional space of the 3-dimensional original object displayed as the 2-dimensional picture, an unnatural picture is resulted in.
To put it in detail, a 3-dimensional model representing a house drawn as a 2-dimensional picture shown in FIG. 1A is taken as an example. Assume that characters are added to walls of the house without taking orientations of the walls into consideration as shown in FIG. 1B. In this case, the added characters do not appear to have been drawn on the walls. In addition, an attempt is made to add a cubic room to a wall of the house without taking the orientation of the wall into consideration as shown in FIG. 1C. In this case, by merely drawing a cubic room, a natural result cannot be obtained.
A cylinder drawn as a 2-dimensional picture shown in FIG. 2A is taken as another example. Assume that characters are added to the side surface of the cylinder without taking the orientation of the side surface into consideration as shown in FIG. 2B. In this case, the added characters do not appear to have been indeed drawn on the side surface.
Thus, when doing 2D-painting work to add a string of characters or a figure to a 2-dimensional picture representing a 3-dimensional object, it is necessary to draw the characters or the figure by changing the shape of the characters or the figure to match the orientations of the 3-dimensional object in order to prevent an unnatural drawing from being resulted in. In order to carry out operations to draw such a drawing, however, a skill is required to a certain degree.
It is thus an object of the invention addressing the problem described above to provide a picture-processing apparatus and a picture-processing method that can be used for easily carrying out 3-dimensional editing work on a 3-dimensional object shown as a 2-dimensional picture.
A picture-processing apparatus provided by the present invention is characterized in that the apparatus comprises a computation means for computing a transformation formula prescribing an inter-drawing relation between a projection drawing of a surface composing a 3-dimensional object displayed on a 2-dimensional picture and an expansion drawing of the surface and a correction means for correcting the inter-drawing relation prescribed by the transformation formula and outputting a new inter-drawing relation as a result of correction.
The picture-processing apparatus described above may be further provided with a projection-drawing-transforming means for transforming a projection drawing of each of a plurality of surfaces composing a 3-dimensional object into an expansion drawing of the surface and a connection means for creating a joint drawing by joining expansion drawings of the surfaces in accordance with connection relations each associated with one of the surfaces.
The correction means is capable of correcting an inter-drawing relation so that each point on a side common to a first surface of an expansion drawing and a second surface adjacent to the first surface corresponds to the same point on a projection drawing.
The correction means is also capable of correcting an inter-drawing relation so that a point on a side common to a first surface of an expansion drawing and a second surface adjacent to the first surface corresponds to a point located on a projection drawing and represented by an average value of a first point and a second point where the first point is a point located on the projection drawing and obtained as a result of transformation of the point on the common side based on a transformation formula for the first surface whereas the second point is a point located on the projection drawing and obtained as a result of transformation of the point on the common side based on a transformation formula for the second surface.
The picture-processing apparatus described above may be further provided with a processing means for processing a joint drawing and an expansion-drawing-transforming means for transforming an expansion drawing of each of a plurality of surfaces composing a joint drawing completing processing carried out by the processing means into a projection drawing of the surface on the basis of the new inter-drawing relation.
The computation means is also capable of computing a transformation formula for a surface of a 3-dimensional object from information on the shape of a surface and a characteristic point on a projection drawing of the surface.
The computation means is also capable of computing a function M"psgr" or the inverse function thereof as a transformation formula where notation "psgr" denotes a function of mapping an expansion drawing onto a surface of a 3-dimensional object in a 3-dimensional space and notation M denotes a function of projecting the 3-dimensional object on a screen as a 2-dimensional picture.
A picture-processing method provided by the present invention is characterized in that the method comprises the steps of computing a transformation formula prescribing an inter-drawing relation between a projection drawing of a surface composing a 3-dimensional object displayed on a 2-dimensional picture and an expansion drawing of the surface and correcting the inter-drawing relation prescribed by the transformation formula and outputting a new inter-drawing relation as a result of correction.
A recording medium provided by the present invention is characterized in that the medium is used for recording a program comprising the steps of computing a transformation formula prescribing an inter-drawing relation between a projection drawing of a surface composing a 3-dimensional object displayed on a 2-dimensional picture and an expansion drawing of the surface and correcting the inter-drawing relation prescribed by the transformation formula and outputting a new inter-drawing relation as a result of correction.